Reactive azo dyes

ABSTRACT

The present invention relates to reactive azo dyes of the formula (I) or an alkali metal salt thereof, wherein A is formula (i) or (ii) C is an optionally substituted aromatic or heteroaromatic residue; and R1, R2, B, D, Y, a, b, c, d and n are defined as given in claim 1, a process for preparing said dyes and a process for colouring fibre material, which comprises applying thereto said dyes.

[0001] This invention relates to reactive azo dyes containing each of atriazine ring and at least one reactive vinyl sulphone group (orprecursor thereof) and at least two azo groups. Such dyes are disclosedin, for example, EP-A-0623655, EP-A-0685532 and EP-A-076469 and typicaldyes are as follows:-

[0002] However, none of the dyes disclosed in the abovementioneddocuments provide a particularly strong or bright yellow or reddishyellow shade with good migration properties, excellent build-up and goodfastness properties.

[0003] Thus, the problem addressed by the invention is to provide such adye capable of giving, particularly on cellulosic fabrics, a strong,bright yellow or reddish yellow shade with good migration properties,excellent build-up and which dyes are particularly easy and economicalto produce.

[0004] We find surprisingly that it is possible to solve theabovementioned problems by the use of an azo dye containing, on the onehand, a monoazo dye component based on sulpho-J-acid as couplingcomponent and a markedly electron deficient aromatic amine as diazocomponent and, on the other hand, an azo dye component containing eachof a phenylene group and an aromatic group or hetero aromatic group,each dye component being linked, via an amino linkage to a triazinegroup, the second dye component being so linked via the phenylene group.

[0005] Thus, according to one aspect the invention provides an azo dyeof the formula (I)

[0006] or an alkali metal salt thereof:

[0007] wherein: each of R¹ and R² independently is hydrogen, optionallysubstituted C₁₋₄ alkyl or optionally substituted phenyl;

[0008] A is

[0009] in which formula (i), c is zero or 1;

[0010] in which formula (ii), d is 1, 2 or 3 and a group SO₃H is orthoto the azo group; and

[0011] in which formula (i) or (ii), Y is the group —CH═CH₂; —CH₂CH₂U(wherein U is a leaving group); or —CH₂CH═CH₂;

[0012] B is fluorine; chlorine; the group OR³ (in which R³ is hydrogen,C₁₋₄ alkyl or phenyl); the group NR⁴R⁵ (in which each of R⁴ and R⁵independently is hydrogen, C₁₋₄ alkyl or phenyl; or each of R⁴, R⁵ and Ntogether form an optionally substituted aromatic heterocyclic ring); thegroup ⁺NR⁶R⁷R⁸ (in which each of R⁶, R⁷ and R⁹ independently is C₁₋₄alkyl or phenyl or each of R⁶, R⁷ and R⁸ and N together form anoptionally substituted aromatic heterocylcic ring); or the group SR⁹ (inwhich R⁹ is hydrogen, C₁₋₄ alkyl or phenyl);

[0013] C is an optionally substituted aromatic or heteroaromaticresidue;

[0014] D is methyl, methoxy, amino, acylamino or ureido;

[0015] a is zero, 1 or 2;

[0016] b is zero, 1 or 2 and when b is 2 each D is independent of theother.

[0017] Preferably, the substituent D is methyl, methoxy, acylamino orureido and the substituent B is preferably chlorine or a 3- or4-carboxypyridinium salt derived respectively from nicotinic andisonicotinic acid.

[0018] In the above dye, the group A preferably; has the formula

[0019] wherein

[0020] e is —SO₂CH₂CH₂OSO₃H and f is absent; or

[0021] e is —SO₃H and f is SO₂CH₂CH₂OSO₃H.

[0022] A preferred azo dye has the formula

[0023] wherein each of R², C, D a, b, e and f is as defined above.

[0024] More preferably in the azo dye of the formula (I¹), at least oneof the groups SO₃H or D is ortho to the azo group linking to the groupC.

[0025] In one range of dyes of the formula (I¹) which is preferred, a is1 or 2 and b is zero. More preferably, the group C is a heteroaromaticgroup, still more preferably a pyridonyl, pyrazolonyl,2,6-diaminopyridinyl or 4-carboxy-2,6-dihydroxypyridinyl group, or is ahydroxynaphthalene group.

[0026] In another range of dyes of the formula (I) which is preferred ais zero or 1, b is 1 or 2 and D, or each D independently, is ureido,(C₁₋₄ alkyl)carbonylamino, C₁₋₄ alkoxy or C₁₋₄ alkylthio.

[0027] For such dyes within this other range, a preferred group C hasthe formula (iv)

[0028] wherein

[0029] Ar¹ is an aromatic diazo component;

[0030] g is zero, 1, 2, 3 or 4;

[0031] h is zero, 1, 2 or 3; and

[0032] P, or each P independently, is C₁₋₄ alkyl, nitro, —SO₂NR⁸ (inwhich R⁸ is hydrogen, C₁₋₄ alkyl or phenyl), carboxyl, cyano, SO₂Y¹ (inwhich Y¹ is vinyl, allyl or CH₂CH₂V, where V is a leaving grup) or—NHAr² [in which Ar² is an aromatic residue substituted by at least onegroup T, the group T, or each group T independently, being selected fromcyano, carboxyl, sulphonic acid and SO₂Y² (in which Y² is vinyl, allylor CH₂CH₂W (where W is a leaving group)].

[0033] More preferably, at least one group P is a group SO₂Y¹, where Y¹is as defined above or a group NHAr² substituted by a group T, whichgroup T is the group SO₂Y², in which Y² is as defined above.

[0034] Preferred values of Y¹ and Y² independently are —CH═CH₂;—CH₂—CH═CH₂; —CH₂CH₂Cl, —CH₂CH₂Br; —CH₂CH₂F; —CH₂CH₂OSO₃H; —CH₂CH₂SSO₃H;—CH₂CH₂OCOCH₃, —CH₂CH₂OPO₃H₂; —CH₂CH₂OCOC₂H₅; —CH₂CH₂OSO₂NR⁹ (in whichR⁹ is hydrogen, C₁₋₄ alkyl or phenyl); and —CH₂CH₂OSO₂R¹⁰ (in which R¹⁰is hydrogen, C₁₋₄ alkyl or phenyl).

[0035] Most preferably C is the group

[0036] Typical azo dyes embodying the invention have the formula

[0037] wherein Z is selected from

[0038] Another typical azo dye embodying the invention has the formula

[0039] An azo dye of the formula (I), given and defined above may beprepared by a process which comprises reacting a triazine dye of theformula (II)

[0040] wherein each of R¹, A and B is as defined above and Hal is ahalogen atom;

[0041] with an azo dye of the formula (III)

[0042] wherein each of a, b, R², C and D is as defined above.

[0043] The process is preferably carried out in an aqueous solution atpH 4-6 and at a temperature of at least 30° C.

[0044] The triazine dye of the formula (II) may be prepared bydiazotising an amine of the formula (IV)

A—NH₂  (IV)

[0045] wherein A is as defined above and coupling the diazotised amineof the formula (IV) to a triazine compound of the formula (V)

[0046] wherein each of R¹ and B is as defined above and Hal is a halogenatom, to obtain the triazine dye of the formula (II).

[0047] Typically, diazotisation of the amine is carried out in an acidmedium at a pH of about 2-5, using, for example, acetic, propionic orhydrochloric acid in the presence of a nitrosating agent, such asnitrosyl sulphuric acid, an alkali metal nitrite (e.g sodium nitrite) ora C₁₋₄ alkyl nitrite (e.g. methyl nitrite) at a temperature of from ⁻10°C. to 10° C.

[0048] The coupling reaction may be carried out by adding the diazotisedamine of the formula (IV), to the triazine compound of the formula (V)in water at a temperature of from 0 to 10° C.

[0049] The triazine compound of the formula (V), given and definedabove, may be prepared by reacting an aminonaphthalenesulphonic acidcompound of the formula (VI)

[0050] with a cyanuric halide of the formula (VII)

[0051] wherein each Hal is a halogen atom and B is as defined above, toform the triazine compound of the formula (V).

[0052] The reaction may be carried out by adding the aminonaphthalenesulphonic acid compound of the formula (VI) dropwise to a slurry of thecyanuric halide of the formula (VII) in an ice/water/acetone mixture.

[0053] When in the azo dye of the formula (III), a is 1 or 2, b is zeroand C is the residue of a heteroaromatic coupling component the azo dyeof the formula (III) may be prepared by acylating a diamine of theformula (VIII)

[0054] where a is zero, 1 or 2 to form an amine of the formula (IX),

[0055] where a is zero, 1 or 2 and Ac is an acyl group, diazotising theamino of the formula (IX) and coupling the diazotised amine to acoupling agent of the formula

C—H

[0056] where C is as defined above to form, after deacetylation, the azodye of the formula (III).

[0057] When, in the azo dye of the formula (III), a is zero or 1, b is 1or 2 and D, or each D independently, is ureido, (C₁₋₄ alkyl)carbonylamino, C₁₋₄ alkoxy or C₁₋₄ alkylthio and the group C is a group (iv)

[0058] wherein each of Ar¹, P, g, and h is as defined above, the azo dyeof the formula (III) may be prepared by diazotising an amine of theformula (X)

[0059] wherein each of Ar¹, P, g and h is as defined above, and couplingthe diazotised amine with a coupling agent of the formula (XI)

[0060] where D is as defined above, a is zero or 1 and b is 1 or 2.

[0061] In either of the above reactions, the diazotisation and couplingmay be carried out in a manner analogous to that described in relationto the preparation of the triazine dye of the formula (II).

[0062] Dyes embodying the invention may be applied alone or in admixturewith other dyestuffs.

[0063] Although in this specification, dye formulae have been shown inthe form of their free acid, the invention also includes dyes andprocesses using dyes in the salt form, particularly their salts withalkali metals such as the potassium, sodium, lithium or mixedsodium/lithium salt.

[0064] The dyes may be used for dyeing, printing or ink-jet printing,for example of textile materials and paper.

[0065] The process for colouration is preferably preformed at a pH of7.1 to 13, more preferably 10 to 12 pH levels above 7 can be achieved byperforming the process for colouration in the presence of anacid-binding agent. They can be applied at any temperature from roomtemperaure (e.g. 15° C.) to 80° C., preferably from 40 to 60° C.

[0066] The substrate may be any of fibre material such as a textilematerial, leather, paper, hair or film, but is preferably a natural orartifiical textile material containing amino or hydroxyl groups, forexample textile material such as wool, silk, polyamides and modifiedpolyacrylonitrile fibres, and more preferably a cellulose, for example,that commercially available as Tencel. For this purpose the dyes can beapplied to the textile materials at a pH above 7 by, for example,exhaust dyeing, padding or printing. Textile materials are colouredbright shades and possess good fastness to light and wet treatments suchas washing.

[0067] The new dyes are particularly valuable for colouring cellulosictextile materials. For this purpose, the dyes are preferably applied tothe cellulosic textile material at a pH above 7 in conjunction with atreatment with an acid-brinding agent.

[0068] Preferred acid-binding agents include alkali metal carbonates,bicarbonates, hydroxides, metasilicates and mixtures thereof, forexample sodium bicarbonate, sodium carbonate, sodium metasilicate,sodium hydroxide and the corresponding potassium salts. The dyes benefitfrom excellent build-up and high fixation.

[0069] The new dyes can be applied to textile materials containing aminegroups, such as wool and polyamide textile materials, from a neutral tomildly alkaline dyebath. The dyeing process can be carried out at aconstant or substantially constant pH, that it to say the pH of thedyebath remains constant or substantially constant during the dyeingprocess, or if desired the pH of the dyebath can be altered at any stageof the dyeing process.

[0070] The dyes may be in liquid or solid form, for example in granularor powdered form.

[0071] According to yet another aspect of the invention there isprovided a process for colouring a fibre material containing a groupreactive with a reactive dye or a fibre blend containing the fibrematerial, which method comprises applying thereto a dye of the formula(I), given and defined above, preferably at a pH above 7.

[0072] Preferred embodiments of the invention will now be described inmore detail with reference to the following Examples, in which all partsare by weight unless otherwise stated.

EXAMPLE 1

[0073] Preparation of the dye:

[0074] The process may be represented by the following reaction scheme.

[0075] A solution of 2-amino-5-hydroxy-1,7-naphthalene disulphonic acid(50) (39.0 g, 0.08 mol) in water (500 mls) was added dropwise to aslurry of cyanuric chloride (51) (16.2 g, 0.088M) in anice/water/acetone mixture and allowed to stir for 1 hr to provide asolution of the dichlorotriazinyl complex (52).

[0076] Separately, 2N sodium nitrite solution was added dropwise to anice cold slurry of 2-amino-5-(β-sulphatoethylsulphone) benzenesulphonicacid (45.2 g, 0.093M) (4) and concentrated HCl (30 mls) in water (500mls). After 1 hr, excess nitrous acid was destroyed by the addition ofsulphamic acid, leaving a solution of the diazonium salt (53). Thesolution of the diazonium salt (53) was then added to thedichlorotriazine (53) solution and the mixture allowed to warm to roomtemperature while maintaining the pH at 6. After 4 hrs the resultingprecipitate was filtered off and dried to give the reddish yellowdichlorotriazinyl dye (70 g) (54). Analytical data were in fullagreement with the expected structure.

[0077] 2N sodium nitrite solution was added dropwise to an ice coldsolution of 2(2-sulpho-4-nitrophenylamino)-5-amino-1,4-benzenedisulphonic acid (6.9 g, 0.01 mol) and concentrated HCl (3mls) in water(100 mls). After 1 hr, excess nitrous acid was destroyed by the additionof sulphamic acid leaving a solution of the diazonium salt (55). Thesolution of the diazonium salt (55) was then added to a slurry ofmeta-ureidoaniline (56) (2.8 g, 0.01 mol) in water (100 mls) and themixture allowed to warm to room temperature over night maintained at pH4. The product was precipitated by the addition of methylated spirits,filtered off and dried to give the monoazoamine dye (57) (9.1 g).Analytical data were in full agreement with the expected structure.

[0078] An aqueous solution of dichlorotriazine dve (54) (5.0 g, 0.0045mol) and monoazoamine dye (57) (5.6 g, 0.0045 mol) in water (100 mls)maintained at pH 5 was heated at 65° C. for 2 hrs. The resultingsolution was cooled and the product precipitated by the addition ofmethylated spirits. The precipitate was filtered off and dried to givethe reactive dye (1) of Example 1 (6.6 g) λmax=470 nm ε=76306.Analytical data were in full agreement with the expected structure.

EXAMPLE 2

[0079] Preparation of the dye:

[0080] The process may be represented by the following reaction scheme.

[0081] A solution of 2-amino-5-hydroxy-1,7-naphthalene disulphonic acid(50) (9.72 g, 0.02 mol) in water (100 mls) was added dropwise to aslurry of cyanuric chloride (51) (4.1 g, 0.022 mol) in anice/water/acetone mixture and allowed to stir for 1 hr furnishing asolution of the dichlorotriazinyl complex (52).

[0082] A slurry of6-amino-4-(β-sulphatoethylsulphone)-1,3-benzenedisulphonic acid (16.5 g,0.037 mol) and NaNO₂ (0.041 mol) in water (150 mls) was added dropwiseto ice/water (150 g) and concentrated HCl. After 30 mins excess nitrousacid was destroyed with sulphamic acid, leaving a solution of thediazonium salt (58). ⅔ of the diazonium salt (58) solution was added tothe dichlorotriazine solution and the mixture allowed to warm to roomtemperature maintaining the pH at 6. After 1 hr the resultingprecipitate was filtered off and shown to be the dichlorotriazinylintermediate (59).

[0083] A solution of a monoazoamine dyebase (60) (0.007 mol) and thedichlorotriazine (59) (0.009 mol) in water (250 mls) was heated to 50°C. and the pH maintained at 6 for 4 hrs. The product was precipitated bythe addition of methylated spirits, filtered off and dried to give thereactive dye (2) of Example 2 (10.6 g) λmax=464 nm ε=55500. Analyticaldata were in full agreement with the expected structure.

EXAMPLE 3

[0084] Preparation of the dye:

[0085] The process may be represented by the following reaction scheme.

[0086] 2N NaNO₂ (18 mls, 0.036 mol) was added dropwise to a solution of2-amino-5-acetamido-benzene sulphonic acid (14 g, 0.033 mol) in water(250 mls) with concentrated HCl (8.5 mls), cooled to 0° C. The solutionwas stirred cold for 2 hrs before destroying excess nitrous acid byaddition of sulphamic acid, to give a solution of a diazonium salt (62).

[0087] Half of the available diazonium salt solution (62) was addedslowly to a stirred solution of citrazinic acid (63) (2.55 g, 0.016 mol)in water (100 mls) adjusted and maintained at pH7.

[0088] After 30 mins the coupling was complete and amonoazo-N-acetylamino dye base was precipitated by the addition ofisopropyl alcohol. The N-acetyl dyebase was then dissolved in 2N sodiumhydroxide and heated at 60° C. for 2 hrs before cooling and acidifyingto pH2 with concentrated HCl to precipitate a dark solid. The solid wasfiltered off and dried to give the monoazoamino dyebase (64).

[0089] An aqueous solution of a dichlorotriazine dye (61) (3 g, 0.003mol; prepared as described in Example 1) and the monoazoamino dyebase(64) (1.2 g, 0.003 mol) in water (100 mls) was adjusted to pH5 andheated at 60° C. for 2 hrs. The product was precipitated by addition ofmethylated spirits, filtered off and dried to give the reactive dye (35)of Example 3 as an orange powder (3.5 g) λmax=460 nm ε=62000. Analyticaldata were in full agreement with the expected structure. EXAMPLE 4

[0090] Preparation of the dye:

[0091] The proceess may be represented by the following reaction scheme.

[0092] Reddish-yellow dichlorotriazinyl dye (54) was prepared as inExample 1. 2N sodium nitrite solution was added dropwise to an ice coldsolution of 2-amino-5-(β-sulphatoethylsulphone) benzene-sulphonic-acid(16.75 g, 0.025 mol) and concentrated HCl (6 mls) in water (200 mls).After 1 hour, excess nitrous acid was destroyed by the addition ofsulphamic acid leaving a solution of the diazonium salt (65). Thesolution of the diazonium salt (65) was then added to a slurry ofmeta-ureidoaniline (56) (6.75 g, 0.025 mol) in water (100 mls) and themixture allowed to warm to room temperature over 2 hours maintained atpH 5.5. The product was precipitated by the addition of methylatedspirits, filtered off and dried to give the monoazoamine dve (66) (14.1g). Analytical data were in full agreement with the expected structure.

[0093] An aqueous solution of the dichlorotriazinyl dye (54) (5.0 g,0.0053 mol) and the monoazoamine dye (66) (5.4 g, 0.0053 mol) in water(200 mls) maintained at pH5 was heated at 50° C. for 5 hours Theresulting solution was cooled and the product precipitated by theaddition of methylated spirits. The precipitate was filtered off anddried to give the reactive dye (41) (6.0 g) λmax=462 nm ε=50000.Analytical data were in full agreement with the expected structure.

EXAMPLES 5-45

[0094] In each of the following dyes, a triazine ring carries respectivefirst and second yellow monoazo dye components, a first of which isderived from sulpho-J-acid as a coupling component. The second yellowmonoazo dye components are also derived from a coupling component and adiazotized amine component.

[0095] The dyes of Examples 5-36 and 41-45 (dyes 3, 5-12, 14-16, 18-19,21-34, 36-40 and 42-45) were prepared by the method of Example 1, sothat the residue derived from the coupling component is linked to thetriazine ring).

[0096] The dyes of Examples 36-40 (dyes 4, 13, 17, 20 and 35) wereprepared by the method of Example 3, so that the residue derived fromthe diazotised amine component is linked to the triazine ring.

[0097] Each of the dyes of Examples 5-45 (dies 3-34, 36-40 and 42-45)has the formula

Example Z Dye λ (max) 5

(3) 465 6

(5) 477 7

(6) 476 8

(7) 472 9

(8) 472 10

(9) 470 11

(10) 471 12

(11) 468 13

(12) 470 14

(14) 470 15

(15) 472 16

(16) 473 17

(18) 473 18

(19) 473 19

(21) 469 20

(22) 474 21

(23) 474 22

(24) 474 23

(25) 406 24

(26) 470 25

(27) 469 26

(28) 412 27

(29) 476 28

(30) 475 29

(31) 473 30

(32) 470 31

(33) 466 32

(34) 476 33

(36) 473 34

(37) 475 35

(38) 475 36

(39) 472 37

(4) 476 38

(13) 469 39

(17) 421 40

(20) 466 41

(40) 470 42

(42) 471 43

(43) 468 44

(44) 471 45

(45) 470

[0098] The above reactive dyes embodying the invention contain a firstmonoazo component derived from sulpho-J-acid as coupling component and astrongly electron withdrawing diazo component giving a bright yellowshade, which may be matched and thereby enhanced by a second monoazocomponent, itself providing a bright yellow shade. Such dyes may thus beprovided with an excellent strong and bright shade. They are found alsoto have excellent build-up and good migration properties and arerelatively inexpensive, especially given the depth of shade achieved,and easy to prepare. They also exhibit beneficial fastness properties,especially excellent light and wash fastness.

1. An azo dye of the formula (I)

or an alkali metal salt thereof; wherein: each of R¹ and R²independently is hydrogen, optionally substituted C₁₋₄ alkyl oroptionally substituted phenyl; A is

in which formula (i), c is zero or 1; in which formula (ii), d is 1, 2or 3 and a group SO₃H is ortho to the azo group; and in which formula(i) or (ii), Y is the group —CH═CH₂; —CH₂CH₂U (wherein U is a leavinggroup); or —CH₂CH═CH₂; B is fluorine; chlorine; the group OR³ (in whichR³ is hydrogen, C₁₋₄ alkyl or phenyl); the group NR⁴R⁵ (in which each ofR⁴ and R⁵ independently is hydrogen, C₁₋₄ alkyl or phenyl; or each ofR⁴, R⁵ and N together form an optionally substituted aromaticheterocyclic ring); the group ⁺N R⁶ R⁷ R⁹ (in which each of R⁶, R⁷ andR⁹ independently is C₁₋₄ alkyl or phenyl or each of R⁵, R⁷, R⁹ and Ntogether form an optionally substituted heterocylic ring); or the groupSR⁹ (in which R⁹ is hydrogen, C₁₋₄ alkyl or phenyl); C is an optionallysubstituted aromatic or hetero aromatic residue; D is methyl, methoxy,amino, acylamino or ureido; a is zero, 1 or 2; b is zero, 1 or 2 andwhen b is 2 each D is independent of the other.
 2. An azo dye accordingto claim 1, wherein D is methyl, methoxy, acylamino or ureido.
 3. An azodye according to claim 1 or claim 2, wherein A is the group

wherein e is —SO₂CH₂CH₂OSO₃H and f is absent; or e is —SO₃H and f is—SO₂CH₂CH₂OSO₃H.
 4. An azo dye according to claim 1, claim 2 or claim 3,wherein B is chlorine or is a 3- or 4-carboxypyridium salt derivedrespectively from nicotinic or isonicotinic acid.
 5. An azo dyeaccording to claim 3 or claim 4 of the formula

wherein each of R², C, D, a and b is as defined in claim 1 and each of eand f is as defined in claim
 2. 6. An azo dye according to claim 5,wherein at least one of the groups SO₃H or D is ortho to the azo grouplinking to the group C.
 7. An azo dye according to any preceding claim,wherein a is 1 or 2 and b is zero.
 8. An azo dye according to claim 6 orclaim 7, wherein C is a heteroaromatic group.
 9. An azo dye according toclaim 8, wherein the heteroaromatic group is a pyridonyl, pyrazolonyl,2,6-diaminopyridinyl or 4-carboxy-2,6-dihydroxypyridinyl group.
 10. Anazo dye according to claim 7, wherein C is a hydroxynapthalene group.11. An azo dye according to any one of claims 1 to 6, wherein a is zeroor 1, b is 1 or 2 and D, or each D independently is ureido, (C₁₋₄ alkyl)carbonylamino, C₁₋₄ alkoxy or C₁₋₄ alkylthio.
 12. An azo dye accordingto claim 4 or claim 11, wherein the group C is a group (iv)

wherein: Ar¹ is an aromatic diazo component; g is zero, 1, 2, 3 or 4; his zero, 1, 2, or 3; and P, or each P independently, is C₁₋₄ alkyl,nitro, —SO₂NR⁸ (in which R⁸ is hydrogen, C₁₋₄ alkyl or phenyl),carboxyl, cyano, SO₂Y¹ (in which Y¹ is vinyl, allyl or CH₂CH₂V, where Vis a leaving group) or —NHAr² [in which Ar² is an aromatic residuesubstituted by at least one group T, the group T, or each group Tindependently, being selected from cyano, carboxyl, sulphonic acid andSO₂Y² (in which Y² is vinyl, allyl or CH₂CH₂W (where W is a leavinggroup)].
 13. An azo dye according to claim 12, wherein at least onegroup P is a group SO₂Y¹, where Y¹ is as defined in claim
 12. 14. An azodye according to claim 13, where the group C is of the formula


15. An azo dye according to claim 12 wherein at least one group P is agroup NHAr² substituted by a group T, which group T is the group SO₂Y²,in which Y² is as defined in claim
 12. 16. An azo dye according to claim12, wherein at least one of the moieties Y¹ and Y² is present and is,independently, —CH═CH₂; —CH₂—CH═CH₂; —CH₂CH₂Cl; —CH₂CH₂Br; —CH₂CH₂F;—CH₂CH₂OSO₃H; —CH₂CH₂SSO₃H; —CH₂CH₂OCOCH₃; —CH₂CH₂OPO₃H₂;—CH₂CH₂OCOC₂H₅; —CH₂CH₂OSO₂NR⁹ (in which R⁹ is hydrogen, C₁₋₄ alkyl orphenyl); and —CH₂CH₂OSO₂R¹⁰ (in which R¹⁰ is hydrogen, C₁₋₄ alkyl orphenyl).
 17. An azo dye of the formula

wherein Z is selected from


18. An azo dye of the formula


19. A process for preparing an azo dye of the formula (I), given anddefined in claim 1, which process comprises reacting a triazine dye ofthe formula (II)

wherein each of R¹, A and B is as defined in claim 1 and Hal is ahalogen atom; with an azo dye of the formula (III)

wherein each of a, b, R², C and D is as defined in claim
 1. 20. Aprocess according to claim 19 which is carried out in an aqueoussolution at pH 4-6 and at a temperature of at least 30° C.
 21. A processaccording to claim 19 or claim 20, which includes the preliminary stepof preparing the triazine dye of the formula (II) by diazotising anamino of the formula (IV) A—NH₂   (IV)wherein A is as defined in claim 1and coupling the diazotised amine of the formula (IV) to a triazinecompound of the formula (V)

wherein each of R¹ and B is as defined in claim 1 and Hal is a halogenatom to obtain the triazine dye of the formula (II).
 22. A processaccording to claim 21, wherein the diazotisation is carried out in anacid medium at a pH of about 2-5, in the presence of a nitrosating agentat a temperature of from −10° C. to 10° C.
 23. A process according toclaim 20 or claim 22, wherein the coupling is carried out by adding thediazotised amine of the formula (IV) to the triazine compound of theformula (V) in water at a temperature of from 0 to 10° C.
 24. A processaccording to any one of claims 21 to 23, which includes the preliminarystep of preparing the triazine compound of the formula (V), given anddefined in claim 21, by reacting an aminonaphthalenesulphonic acidcompound of the formula (VI)

with a cyanuric halide of the formula (VII)

wherein each Hal is a halogen atom and B is as defined in claim 1, toform the triazine compound of the formula (V).
 25. A process accordingto claim 24, which is carried out by adding the aminonaphthalenesulphonic acid compound of the formula (VI) dropwise to a slurry of thecyanuric halide of the formula (VII) in an ice/water/acetone mixture.26. A process according to any one of claims 19 to 25, wherein, in theazo dye of the formula (III), a is 1 or 2, b is zero and C is theresidue of a heteraromatic coupling component and the process includesthe preliminary step of preparing the azo dye of the formula (III) byacylating a diamine of the formula (VIII)

where a is zero, 1 or 2, to form an amine of the formula (IX)

where a is zero, 1 or 2 and Ac is an acyl group, diazotising the amineof the formula (IX), coupling the diazotised amine to a coupling agentof the formula C—H where C is as defined in claim 1, and deacetylatingthe resultant product to form the azo dye of the formula (III).
 27. Aprocess according to any one of claims 21 to 25, wherein, in the azo dyeof the formula (III) a is zero or 1, b is 1 or 2 and D, or each Dindependently is ureido (C₁₋₄ alkyl)carbonylamino, C₁₋₄ alkyl or C₁₋₄alkylthio and the group C is a group (iv)

wherein each of Ar¹, P, g and h is as defined in claim 12, and theprocess includes the preliminary step of preparing the azo dye of theformula (III) by diazotising an amine of the formula (X)

wherein each of Ar¹, P, g and h is as defined in claim 12 and couplingthe diazotised amine with a coupling agent of the formula (XI).

where D is as defined in claim 1, a is zero or 1 and b is 1 or
 2. 28. Aprocess for colouring fibre material containing a group reactive with areactive dye or a fibre blend containing the fibre material, whichmethod comprises applying thereto a reactive dye of the formula (I),given and defined in claim 1.